There is a fundamental gap in the availability of evidence-based treatments for disruptive sleep problems among children with Down syndrome (DS). Lack of such treatments represents an important problem because 52-69% of these individuals experience behaviorally-based difficulties with sleep initiation, sleep maintenance and early wakening's. These problems reduce the amount and quality of sleep, and have been linked to daytime inattention and behavior problems and increased parental burden. Without evidence-based behavioral interventions, treatment of disruptive sleep problems will remain suboptimal. Despite promising findings, the evidence base for behavioral sleep treatment (BST) in DS is limited. Controlled clinical trials are the clear next step towards empirically-based treatment for behavioral sleep problems in children with DS. BST have been successfully used to treat behavioral sleep problems among children with autism spectrum disorder. Following the same path, the current study adopts these BST techniques and adapts them to fit the most common DS phenotype. The overall objective of this application is to test the efficacy of a manualized BST using a randomized control trial with children with DS. Our rationale for working with this population is that disruptive sleep problems are a clinically important and highly prevalent condition among these children, and that the DS behavioral phenotype will require adaptations to current BST. We propose three specific aims: 1) To test the efficacy of manualized BST for improving the sleep of children with DS. 2) To test the impact of the BST on improving the daytime functioning of children with DS. 3) To test whether the BST, which focuses only on the child's sleep, improves caregivers' sleep and stress. To achieve these aims, a randomized control trial will be conducted with 80 children ages 6-17 years with DS experiencing behavioral sleep problems comparing a 5- session parent education BST to an enhanced standard of care parent education control program. Objective and informant-report (both parent and teacher) will be collected on the primary outcome measures of sleep duration, sleep quality, inhibitory control, behavior problems, parental sleep duration, and parental stress. This will be the first randomized clinical trial of a BST developed for this vulnerable population f children. Our research team is uniquely positioned to conduct this work, combining expertise in DS, clinical trials, BST of children with developmental disabilities, and assessment of sleep and related functional outcomes. We anticipate that this small-scale efficacy trial will provide criticl guidance for large-scale, multi-site efficacy and effectiveness work. Our goals are in line with NICHD's research priority to support treatment among individuals with intellectual and developmental disabilities. If the intervention is as efficacious as our preliminary evidence and work with other populations suggest, this would provide a clear evidence base for clinical decision-making to improve the outcomes for the approximately 42,000-58,000 children with DS and disruptive sleep nationwide.